Demographic and Clinical Characteristics of COPD Patients at Different Blood Eosinophil Levels in the UK Clinical Practice Research Datalink

Figures & data

Table 1. Demographic and clinical characteristics for COPD patients and non-COPD matched controls (matched on age, sex and smoking status).

		COPD (n = 27,557)^*		Non-COPD (n = 27,557)
		N	%	N	%
Sex	Male	14,186	51.5	14,186	51.5
	Female	13,371	48.5	13,371	48.5
Age (years)	40–49	859	3.1	859	3.1
	50–59	3,072	11.1	3,072	11.1
	60–69	7,611	27.6	7,611	27.6
	70+	16,015	58.1	16,015	58.1
	Mean (SD)	71.1 (10.6)		71.1 (10.6)
Smoking status	Ex-smoker	16,392	59.5	16,392	59.5
	Never	1,926	7.0	1,926	7.0
	Current	9,239	33.5	9,239	33.5
BMI (kg/m^2)	Underweight (<18.5)	1,123	4.1	477	1.7
	Normal (18.5–24.9)	8,509	30.9	7,953	28.9
	Overweight (25.0–29.9)	9,084	33.0	10,315	37.4
	Obese (≥30.0)	8,405	30.5	7,925	28.8
	Unknown	436	1.6	887	3.2
	Mean (SD)	27.7 (6.3)		27.8 (5.5)
Dyspnea score	MRC 1	3,826	13.9	178	0.6
	MRC 2	9,178	33.3	235	0.9
	MRC 3	6,932	25.2	103	0.4
	MRC 4	4,247	15.4	43	0.2
	MRC 5	1,036	3.8	5	0
	Unknown	2,338	8.5	26,993	98.0
	Mean (SD)	2.6 (1.1)		2.1 (0.9)
GOLD 2006 stage	I (80+)	3,759	13.6	415	1.5
	II (50 to <80)	11,271	40.9	209	0.8
	III (30 to <50)	4,458	16.2	19	0.1
	IV (<30)	766	2.8	-	-
	Unknown	7,303	26.5	26,912	97.7
COPD exacerbations in 12 months	0	15,868	57.6	-	-
prior to index date	1	6,806	24.7	-	-
	2+	4,883	17.7	-	-
Any ICS use during follow up	Yes	18,726	68.0	2751	9.3
History of asthma	Yes	9,833	35.7	2,807	10.2

Index date refers to the COPD diagnosis code date.

^* Basic demographics and disease characteristics for the COPD cohort only were reported previously (21).

BMI, body mass index; COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; MRC, Medical Research Council; SD, standard deviation.

Figure 1. Histogram of blood eosinophil counts (cells/μL) for COPD patients and non-COPD controls in the UK Clinical Practice Research Datalink. Histogram based on absolute (untransformed) values. Note: Only the first blood eosinophil count was used in this analysis. COPD, chronic obstructive pulmonary disease.

Table 2. Mean blood eosinophil counts (cells/μL) among COPD patients by demographic and disease characteristics.

		N	Mean (95% CI)	p value
All		27,552	196.6 (195.1, 198.3)	–
Sex	Female	13,367	181.8 (179.8,183.9)	<0.0001
	Male	14,185	211.7 (209.3,214.2)
Age (years)	40–49	859	206.9 (198.3,215.8)	0.0550
	50–59	3,071	197.4 (192.9,202.0)
	60–69	7,608	198.3 (195.2,201.3)
	70+	16,014	195.2 (193.1,197.4)
Smoking status	Ex-smoker	16,388	198.1 (196.0,200.2)	0.0627
	Never	1,926	197.7 (191.3,204.3)
	Current	9,238	194.0 (191.3,196.7)
BMI	Underweight (<18.5)	1,123	172.1 (164.5,180.0)	<0.0001
	Normal (18.5–24.9)	8,508	191.0 (188.1,193.9)
	Overweight (25.0–29.9)	9,083	200.3 (197.5,203.2)
	Obese (≥30.0)	8,402	202.3 (199.5,205.2)
Dyspnea score	MRC 1	3,825	201.8 (197.4,206.2)	0.0239
	MRC 2	9,177	197.6 (194.9,200.3)
	MRC 3	6,930	195.4 (192.3,198.6)
	MRC 4	4,246	198.7 (194.5,203.0)
	MRC 5	1,036	187.8 (179.3,196.7)
GOLD 2006 stage	I (80+)	3,758	197.3 (193.1,201.6)	0.4633
	II (50 to <80)	11,269	195.7 (193.3,198.2)
	III (30 to <50)	4,456	199.3 (195.4,203.4)
	IV (<30)	766	194.3 (184.8,204.3)
COPD exacerbations in 12 months	0	15,863	194.5 (192.5,196.6)	0.0086
prior to index date	1	6,806	200.2 (196.9,203.5)
	2+	4,883	198.6 (194.6,202.8)
History of asthma	Yes	9,831	205.0 (202.2,207.9)	0.0046
	No	17,721	192.2 (190.2,194.1)

Note: ^*Population mean blood eosinophil count calculated after taking a log transformation of the data (values presented represent back transformed means); N = 5 patients with untransformed value of zero not included in table. Note: Only the first blood eosinophil count was used in this analysis. Index date refers to the COPD diagnosis code date.

BMI, Body Mass Index; CI, confidence interval; COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; MRC, Medical Research Council.

Figure 2. Proportion of blood eosinophil counts “always above”, “fluctuating above and below”, or “never above” cut points of 100, 150, and 300 cells/μL among COPD patients at least two blood eosinophil measurements during follow up (n = 13,463). “Always above” defined as all blood eosinophil counts being greater than or equal to the cut point, “fluctuating above and below” defined as at least one blood eosinophil count less than and at least one blood eosinophil count greater than or equal to the cut point, while “never above” defined as being always less than the cut point.

Figure 3. Proportion of blood eosinophil counts “always above”, “fluctuating above and below”, or “never above” cut points of 100, 150, and 300 cells/μL, among COPD patients at least two blood eosinophil measurements during follow up (n = 13,463), stratified by asthma diagnosis.^**Asthma diagnosis defined as at least two asthma medical codes (anytime during the patient's history prior to the index date). “Always above” defined as all blood eosinophil counts being greater than or equal to the cut point, “fluctuating above and below” defined as at least one blood eosinophil count less than and at least one blood eosinophil count greater than or equal to the cut point, while “never above” defined as being always less than the cut point.

Table 3. Characteristics of COPD patients with blood eosinophil counts “always above”, “fluctuating above and below”, and “never above” 100, 150, and 300 cells/µL among patients at least two blood eosinophil measurements during follow up (n = 13,463).

	100 cells/µL cut point^*				150 cells/µL cut point^*				300 cells/µL cut point^*
	Always above	Both above and below	Never above		Always above	Both above and below	Never above		Always above	Both above and below	Never above
	(n = 11,692)	(n = 1,332)	(n = 439)	p value	(n = 6,872)	(n = 4,059)	(n = 2,532)	p value	(n = 2,587)	(n = 3,583)	(n = 7,293)	p value
Male sex, %	51.9	48.7	43.3	0.0003	55.6	48.5	44.0	<0.0001	62.2	53.7	46.3	<0.0001
Mean age (SD) years	72 (10)	73 (10)	74 (10)	<0.0001	72 (10.4)	73 (10.2)	73 (10.4)	0.0075	73 (10)	73 (10)	72 (10)	0.0691
Smoking status, %
Ex-smoker	63.0	63.4	59.8	0.4159	63.1	63.0	62.4	0.9444	63.5	63.5	62.0	0.2821
Never smoker	6.6	7.4	8.1		6.6	6.8	7.1		7.1	6.8	6.6
Current smoker	30.4	29.1	32.1		30.3	30.2	30.5		29.4	29.7	31.4
Mean BMI (SD) kg/m^2	28.0 (6.3)	26.9 (6.3)	27.1 (7.1)	<0.0001	28.4 (6.2)	27.4 (6.5)	27.1 (6.3)	<0.0001	28.2 (6.1)	27.9 (6.7)	27.7 (6.2)	0.0003
Mean dyspnea score (SD) MRC	2.6 (1.1)	2.7 (1.1)	2.6 (1.1)	0.3738	2.6 (1.1)	2.7 (1.1)	2.6 (1.1)	0.0013	2.6 (1.1)	2.7 (1.1)	2.6 (1.1)	0.0072
GOLD 2006 stage, %
I (80+)	20.5	19.8	22.6	0.8202	20.5	20.3	21.1	0.3472	20.3	20.2	20.6	0.1010
II (50 to <80)	55.9	55.4	55.8		55.4	56.3	55.8		55.1	55.1	56.5
III (30 to <50)	20.3	21.5	18.1		20.7	19.9	20.1		21.2	20.6	20.0
IV (<30)	3.3	3.4	3.5		3.4	3.5	3.0		3.3	4.2	2.9
COPD exacerbations in past 12 months, %
0	56.3	54.4	58.1	0.3096	56.5	54.3	58.6	0.7062	58.1	52.2	57.7	0.2205
1	25.5	24.8	22.8		25.6	25.6	23.9		24.7	26.4	24.5
2+	18.2	20.7	19.1		17.9	20.1	17.5		17.3	21.4	17.7
History of asthma, %	36.9	36.2	33.7	0.3465	37.9	36.0	34.8	0.0094	39.0	37.6	35.4	0.0022

BMI, body mass index; COPD, chronic obstructive pulmonary disease; GOLD, Global initiative for chronic Obstructive Lung Disease; MRC, Medical Research Council; SD, standard deviation.

^* “Always above” defined as all blood eosinophil counts being greater than or equal to the cut point, “fluctuating above and below” defined as at least one blood eosinophil count less than and at least one blood eosinophil count greater than or equal to the cut point, while “never above” defined as being always less than the cut point.

Landis SH, Suruki R, Hilton E, Compton C, Galwey NW. Stability of Blood eosinophil count in patients with COPD in the UK Clinical Practice Research Datalink. COPD 2017;14(4):382–8. doi:10.1080/15412555.2017.1313827. PMID:28569614.

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